Telephone users have been provided with a vast array of different types and forms of communications services in recent years. In addition to traditional wireline telephones, wireless phones and the Internet have become widely accepted as mediums for telecommunications services in modern society. For instance, wireless communications systems and networks have been constructed and interconnected with the wire-line telephone networks to allow mobile devices to communicate with other mobile devices as well as with ordinary stationary telephones. The wireless systems include various infrastructure to service a wide geographic area divided into regions or “cells” with base stations serving one or more such cells and networked mobile switching centers (MSCs) serving one or more base stations, where the MSCs are operatively coupled with one another and other systems by a wireless network and one or more MSCs may be coupled to a wire-based network to provide communications among and between wireless and/or wireline devices. In common cellular communications systems, the communication path is established through various MSCs and intervening networks and the data is sent in digital form over the same path throughout the call session. Wireless fidelity (WiFi) systems have also become popular, in which the telephone communications data is transferred in packets, wherein the transfer path may change during a call, whereby different packets may travel along different routes, with the received packets being reassembled at the recipient device for conversion to analog audio for provision to the subscriber or user.
In addition to traditional wire-line and wireless telecommunications, the Internet has proliferated in recent years to become a popular communications medium in which data is transferred in packets between devices connected to the network. With respect to telecommunications, moreover, the Internet and other packet-switched (e.g., IP-based) networks are now being employed as a medium for telephone traffic, in which voice information is provided in a packetized data stream along with other data streams being used for data transfer, a technology referred to as voice-over-IP (VOIP), wherein IP refers to the Internet Protocol for the data link layer. VOIP telephones and other VOIP terminals can be operatively connected to the Internet by cables using Ethernet cards or other network interfaces, as well as through IP multimedia subsystem (IMS) Wifi networks, in order to provide telephone service regardless of the point of connection with the IP-based network. In this regard, such VOIP terminals are essentially mobile devices that retain the same phone number at any location, whereby users can originate and receive calls and also interface to other services provided over the Internet and IP-based networks generally, regardless of the current terminal location.
911 and other emergency services have been available for some time through conventional telephone systems, wherein a caller dials “911” or other designated number to connect with emergency service providers in the immediate area. In conventional wire-line systems, each telephone is connected to a telephone line in a known location, whereby the providers of 911 emergency services can ascertain the telephone number of a calling party and consult an automatic location identifier (ALI) database or other suitable data store to translate the telephone number to street address and subscriber name information. When a 911 emergency operator or dispatcher receives a call, it may be essential to direct service providers (e.g., fire department, ambulance, police, etc.) to the correct street address quickly to aid the caller, particularly where the caller is unable to vocally provide the address information to the dispatcher. Thus, for conventional fixed-location telephones, the ALI database provides valuable information in the context of 911 calls. However, since VOIP telephones or terminals can be moved, there is a need for improved methods and apparatus for locating VOIP terminals and providing the terminal locations to emergency service providers.